PROC. ENT. SOC. WASH., VOL. 20, NO. 7, OCT., 1918 155 



forms, asymetrical, the right half being somewhat more prolonged than the 

 left. Beneath this right half lies the dextral concealed genital plates, of 

 which there are two, one above the other, while on the opposite side lies 

 the sinistral plate with its slender genital hook. The inferior dextral plate 

 is remarkably different in this new species from that of its near relative 

 apacha. In apacha this plate is armed with a single sharp chitinized tooth 

 as described by Hebard 1 but not very well represented in his figure. In the 

 present species there is a similar chitinized spine and basad of this spine 

 there is a completely chitinized projection as long as the^spine and about 

 as thick but with the apical part noticeably swollen and the tip rounded; 

 just beneath this projection is an elevated ridge with a small tooth at the 

 base of the projection, this ridge with the small tooth is not readily seen 

 except on close and careful examination. In apacha, instead of a projec- 

 tion and elevated toothed ridge there is an unarmed, moderately chitinized 

 and scarcely elevated ridge; the superior dextral plate of these two species 

 differ almost as much as the inferior ones above described. In apacha this 

 superior plate is broadly and roundly excavate on the inner edge, and at 

 the base of this emargination are two elongate sharp completely chitinized 

 teeth situated one above the other, the upper one directed backwards and 

 seen only in completely dissected specimens, and the lower one directed 

 diagonally downwards and generally clearly visible when the subgenital 

 plate is laid aside. In genitalis this superior plate is shaped about as in 

 apacha but at the base of the inner emargination is an apically rounded 

 subclavate projection, vertically flattened, fully chitinized and with a tri- 

 angular tooth on the inner surface, seen only upon careful examination; 

 above this projection is a rounded chitinized shoulder, corresponding to 

 the second acute spine in apacha. This upper dextral plate in both sexes 

 extends backwards over the ventral plate and in the deeply concealed por- 

 tions of the genitalia there are various chitinized ridges which are visible 

 only when the organs are removed and dissected out, and in apacha there 

 is a sharp, slender spine on one of these deep-lying chitinized portions that 

 is apparently wanting in the new species now under discussion. The sinis- 

 tral plate and genital hook are very similar in both species, as are also the 

 cerci and supraanal and subgenital plates. 



The interocular space of all specimens examined is subequal in width 

 with the interocellar space, sometimes a very little greater, in this respect 

 agreeing with apacha. The coloration is uniform in all specimens seen, 

 being rather intensive in degree, the discal shield-shaped spot on the pro- 

 notal disk being very distinct and well defined. The size is generally some- 

 what smaller than in apacha, only one of the five specimens before me being 

 as large as the smallest individual of apacha in the National Museum. 



Female. Unknown, or if specimens of this sex are in the collection they 

 are apparently inseparable from allied forms. 



1 Mem. Amer. Entom. Soc., No. 2, p. 237, pi. ix, fig. 14 (1917). 



